-- first, target an elite creature or NPC so the "gold dragon" target border appears
-- then try running the following scripts:
TargetFrameTexture:SetVertexColor(1,0,0)
-- omits the green and blue channels from the image, giving it a red tint
TargetFrameTexture:SetVertexColor(0,0,1)
-- omits the red and green channels from the image: note the image is mostly black,
-- as the gold color of the dragon image comes primarily from red and green channels
TargetFrameTexture:SetVertexColor(0,0,0)
-- omits all color channels, leaving a black shadow defined by the image's alpha channel
TargetFrameTexture:SetVertexColor(1,1,1)
-- removes vertex shading, returning the image to its original colors